An X-ray photography device for dental practice is known that includes: an X-ray source for irradiating an object with an X-ray beam; an X-ray imaging unit for detecting the X-ray beam transmitted through the object; and a swing drive unit for swinging the X-ray source and the X-ray imaging unit around the object, and is capable of taking a CT photograph and a panoramic photograph (see Japanese Patent Application Publication No. H10-225455). An X-ray photography device described in Japanese Patent Application Publication No. H10-225455 uses a two-dimensional sensor, having a wide detection area as required for taking a CT photograph, as an X-ray imaging unit.